It’s true that pharmaceutical purity is higher, but it’s very much incorrect to say that hospital patients routinely receive higher amounts or doses than street users.
The doses used by chronic opioid, benzo, and stimulant addicts can be absolutely insane compared to even high doses given in medical practice. Even more so after tolerance builds.
This can be a real problem for severe addicts who become hospitalized or end up in the ER because their tolerance is so high that even the high end of doses used in normal patients may do next to nothing in patients with severe addictions.
Addicts also have several factors contributing to the increased severity of their condition: Their route of administration is designed to maximize the ramp up of the dose, which leads to stronger effects, habituation, tolerance, and withdrawal dynamics.
Undergoing many cycles of habituation and withdrawal (missing doses, running out, or just abusing on weekends and trying to stay sober during the week) can actually sensitize addiction problems and exacerbate the problem, even if the doses are not extreme. This is not a problem in a hospital where doses are scheduled and regular.
Finally, the duration of exposure and area under the curve is dramatically different. An addict may be exposed to 100X or 1000X as much of a drug over years due to higher dosing and long term addiction relative to someone in the hospital who undergoes a procedure and then is tapered off.
It’s really misleading to compare opioids or benzos prescribed in a controlled hospital setting to the use by addicts. They are so dramatically different that you can’t compare the addiction and withdrawal dynamics at all.